Intake duct for internal combustion engine

Abstract

An intake duct for an internal combustion engine includes a pipe-shaped shell. The shell includes a first molded product and a second molded product. The first molded product is formed by a plastic molded product and includes an opening extending through the first molded product in the thickness direction. The second molded product is formed by a fiber molded product produced through compression molding. The second molded product includes an air-permeable fitting projection fitted into the opening, and the second molded product is joined with an outer surface of the first molded product.

What is claimed is: 
     
       1. An intake duct for an internal combustion engine, the intake duct comprising:
 a pipe-shaped shell including:
 a first molded product formed by a plastic molded product and including an opening extending through the first molded product in a thickness direction, and 
 a second molded product formed by a fiber molded product produced through compression molding, wherein the second molded product includes an air-permeable fitting projection fitted into the opening, and the second molded product is joined with an outer surface of the first molded product, wherein 
 
 the air-permeable fitting projection is an air-permeable low-compression portion having a first thickness, 
 the second molded product further includes an air-impermeable high-compression portion that is compressed to a higher degree than the air-permeable fitting projection, the air-impermeable high-compression portion having a second thickness that is smaller than the first thickness, and 
 the air-impermeable high-compression portion is not fitted into the opening. 
 
     
     
       2. The intake duct according to  claim 1 , wherein the fitting projection includes a projection end surface that is flush with an inner surface of the first molded product adjacent to the fitting projection, and
 the inner surface of the first molded product defines a part of an inner surface of the intake duct. 
 
     
     
       3. The intake duct according to  claim 1 , wherein
 the shell includes a first segment and a second segment joined with the first segment in a circumferential direction, 
 the first segment is formed by a fiber molded product produced through compression molding and includes an air-permeable and low-compression portion and a high-compression portion that is compressed to a higher degree than the low-compression portion, and 
 the second segment includes the first molded product and the second molded product. 
 
     
     
       4. The intake duct according to  claim 3 , wherein
 the first molded product includes a bottom wall, two opposing walls that are bent and extended from two side edges of the bottom wall and opposed to each other, and two flanges that are bent and extended from the two opposing walls, 
 the two flanges are joined with the first segment, 
 the second molded product includes a bottom portion and two side portions, the two side portions being bent and extended from two side edges of the bottom portion, and 
 the second molded product is joined with the outer surface of the first molded product such that the bottom portion of the second molded product covers the bottom wall of the first molded product and that each side portion of the second molded product covers a corresponding one of the opposing walls of the first molded product. 
 
     
     
       5. An intake duct for an internal combustion engine, the intake duct comprising:
 a pipe-shaped shell including:
 a first molded product formed by a plastic molded product and including an opening extending through the first molded product in a thickness direction, and 
 a second molded product formed by a fiber molded product produced through compression molding, wherein the second molded product includes an air-permeable fitting projection fitted into the opening, and the second molded product is joined with an outer surface of the first molded product, wherein 
 
 the shell includes a first segment and a second segment joined with the first segment in a circumferential direction, 
 the first segment is formed by a fiber molded product produced through compression molding and includes an air-permeable and low-compression portion and a high-compression portion that is compressed to a higher degree than the low-compression portion, 
 the second segment includes the first molded product and the second molded product, 
 the first molded product includes a bottom wall, two opposing walls that are bent and extended from two side edges of the bottom wall and opposed to each other, and two flanges that are bent and extended from the two opposing walls, 
 the two flanges are joined with the first segment, 
 the second molded product is joined with outer surfaces of the bottom wall and the two opposing walls of the first molded product, 
 the opening is one of a plurality of openings arranged in the bottom wall and in the opposing walls, and 
 the fitting projection is one of a plurality of fitting projections arranged on the second molded product and fitted into the corresponding openings. 
 
     
     
       6. The intake duct according to  claim 5 , wherein
 the fitting projection includes a projection end surface that is flush with an inner surface of the first molded product adjacent to the fitting projection, and 
 the inner surface of the first molded product defines a part of an inner surface of the intake duct. 
 
     
     
       7. The intake duct according to  claim 2 , wherein an inner surface of the air-impermeable high-compression portion of the second molded product contacts the outer surface of the first molded product.